representation.h

// Copyright 2017 Google Inc. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
//

#ifndef PACKAGER_MPD_BASE_REPRESENTATION_H_
#define PACKAGER_MPD_BASE_REPRESENTATION_H_

#include "packager/mpd/base/bandwidth_estimator.h"
#include "packager/mpd/base/media_info.pb.h"
#include "packager/mpd/base/segment_info.h"
#include "packager/mpd/base/xml/scoped_xml_ptr.h"

#include <stdint.h>

#include <list>
#include <memory>

namespace shaka {

struct ContentProtectionElement;
struct MpdOptions;

namespace xml {
class XmlNode;
class RepresentationXmlNode;
}  // namespace xml

class RepresentationStateChangeListener {
 public:
  RepresentationStateChangeListener() {}
  virtual ~RepresentationStateChangeListener() {}

  virtual void OnNewSegmentForRepresentation(int64_t start_time,
                                             int64_t duration) = 0;

  virtual void OnSetFrameRateForRepresentation(uint32_t frame_duration,
                                               uint32_t timescale) = 0;
};

class Representation {
 public:
  enum SuppressFlag {
    kSuppressWidth = 1,
    kSuppressHeight = 2,
    kSuppressFrameRate = 4,
  };

  virtual ~Representation();

  bool Init();

  virtual void AddContentProtectionElement(
      const ContentProtectionElement& element);

  virtual void UpdateContentProtectionPssh(const std::string& drm_uuid,
                                           const std::string& pssh);

  virtual void AddNewSegment(int64_t start_time,
                             int64_t duration,
                             uint64_t size);

  virtual void SetSampleDuration(uint32_t sample_duration);

  virtual const MediaInfo& GetMediaInfo() const;

  xml::scoped_xml_ptr<xmlNode> GetXml();

  void SuppressOnce(SuppressFlag flag);

  void SetPresentationTimeOffset(double presentation_time_offset);

  bool GetStartAndEndTimestamps(double* start_timestamp_seconds,
                                double* end_timestamp_seconds) const;

  uint32_t id() const { return id_; }

  void set_media_info(const MediaInfo& media_info) { media_info_ = media_info; }

 protected:
  Representation(
      const MediaInfo& media_info,
      const MpdOptions& mpd_options,
      uint32_t representation_id,
      std::unique_ptr<RepresentationStateChangeListener> state_change_listener);

  Representation(
      const Representation& representation,
      std::unique_ptr<RepresentationStateChangeListener> state_change_listener);

 private:
  Representation(const Representation&) = delete;
  Representation& operator=(const Representation&) = delete;

  friend class AdaptationSet;
  friend class RepresentationTest;

  // Returns true if |media_info_| has required fields to generate a valid
  // Representation. Otherwise returns false.
  bool HasRequiredMediaInfoFields() const;

  // Add a SegmentInfo. This function may insert an adjusted SegmentInfo if
  // |allow_approximate_segment_timeline_| is set.
  void AddSegmentInfo(int64_t start_time, int64_t duration);

  // Check if two timestamps are approximately equal if
  // |allow_approximate_segment_timeline_| is set; Otherwise check whether the
  // two times match.
  bool ApproximiatelyEqual(int64_t time1, int64_t time2) const;

  // Return adjusted duration if |allow_aproximate_segment_timeline_or_duration|
  // is set; otherwise duration is returned without adjustment.
  int64_t AdjustDuration(int64_t duration) const;

  // Remove elements from |segment_infos_| for dynamic live profile. Increments
  // |start_number_| by the number of segments removed.
  void SlideWindow();

  // Remove the first segment in |segment_info|.
  void RemoveOldSegment(SegmentInfo* segment_info);

  // Note: Because 'mimeType' is a required field for a valid MPD, these return
  // strings.
  std::string GetVideoMimeType() const;
  std::string GetAudioMimeType() const;
  std::string GetTextMimeType() const;

  // Get Representation as string. For debugging.
  std::string RepresentationAsString() const;

  // Init() checks that only one of VideoInfo, AudioInfo, or TextInfo is set. So
  // any logic using this can assume only one set.
  MediaInfo media_info_;
  std::list<ContentProtectionElement> content_protection_elements_;

  int64_t current_buffer_depth_ = 0;
  // TODO(kqyang): Address sliding window issue with multiple periods.
  std::list<SegmentInfo> segment_infos_;
  // A list to hold the file names of the segments to be removed temporarily.
  // Once a file is actually removed, it is removed from the list.
  std::list<std::string> segments_to_be_removed_;

  const uint32_t id_;
  std::string mime_type_;
  std::string codecs_;
  BandwidthEstimator bandwidth_estimator_;
  const MpdOptions& mpd_options_;

  // startNumber attribute for SegmentTemplate.
  // Starts from 1.
  uint32_t start_number_ = 1;

  // If this is not null, then Representation is responsible for calling the
  // right methods at right timings.
  std::unique_ptr<RepresentationStateChangeListener> state_change_listener_;

  // Bit vector for tracking witch attributes should not be output.
  int output_suppression_flags_ = 0;

  // When set to true, allows segments to have slightly different durations (up
  // to one sample).
  const bool allow_approximate_segment_timeline_ = false;
  // Segments with duration difference less than one frame duration are
  // considered to have the same duration.
  uint32_t frame_duration_ = 0;
};

}  // namespace shaka

#endif  // PACKAGER_MPD_BASE_REPRESENTATION_H_